Former Palestinian leader Yasser Arafat died of natural causes and was not poisoned by polonium, a Russian forensic institute said on Wednesday.

The conclusion was in line with findings by French experts who earlier this month ruled out the possibility that Arafat died of poisoning, as some had suspected, but in conflict with Swiss scientists’ claims.

“Yasser Arafat died not from the effects of radiation but of natural causes,” Vladimir Uiba, head of the Federal Medico-Biological Agency (FMBA), said according to the Russian Interfax news service.

Arafat died November 11, 2004, at a French military hospital, a month after falling ill at his West Bank headquarters. At the time, French doctors said he died of a stroke and had a blood-clotting problem, but records were inconclusive about what caused that condition.

Palestinian Ambassador to Russia, Fayed Mustafa, was quoted by state RIA Novosti news agency as saying Thursday that the Palestinian authorities respect the Russian experts’ conclusions but consider it necessary to continue research into Arafat’s death.

Uiba said, however, that his agency hasn’t received any Palestinian request for additional studies.

One of the most famous and recent cases of polonium-210 poisoning was that of ex-KGB officer Alexander Litvinenko who died in 2006 after drinking tea laced with the radioactive isotope.

Britain has accused two Russians of the 2006 killing, but Moscow has refused to extradite them.

In 2012, news station Al-Jazeera reported a forensic analysis of Arafat’s underwear, headscarves and other belongings by Switzerland’s Institute for Radiation Physics found trace amounts of the radioactive element polonium, leading to accusations that Israel poisoned the Palestinian leader.

Earlier this year, Arafat’s grave in his Ramallah compound was reopened. Swiss, Russian and French scientists were given samples of the remains and burial soil, but test results showed no indication of poisoning.

Swiss scientists said last month they found at least 18 times the normal level of radioactive polonium in Arafat’s bones, findings which they said “moderately” supported the theory that he was poisoned.

But French scientists who had been looking into Arafat’s death concluded he died of a “generalized infection.”

The Palestinians launched an investigation at the time of Arafat’s death, reportedly encompassing hundreds of statements from Palestinians and non-Palestinians in the West Bank and around the world. No suspects emerged and no arrests were made.

An Israeli expert on radiation quoted by Ynet said the Swiss report of finding polonium was “completely fabricated.” Dr. Ehud Ne’eman said there would be no traces of Polonium 210 if the poison was injected before 2004.

Polonium can be a byproduct of the chemical processing of uranium, but usually it’s made artificially in a nuclear reactor or a particle accelerator. Dozens of countries including Russia, Israel and the US have the nuclear capability to produce polonium.

In November 2012, a leading French doctor who teaches at the Paris hospital where Arafat died told The Times of Israel, based on Arafat’s medical report, that there was “absolutely no way” the Palestinian leader was poisoned.

Arafat’s medical records concluded he died in November 2004 from a stroke “that resulted from a bleeding disorder caused by an unidentified infection,” The New York Times reported in 2005. The paper wrote at the time that the first independent review “suggests that poisoning was highly unlikely.”